The invention relates to a surface cleaning head for cleaning a surface, comprising a dome-shaped, downwardly open housing, in which at least one spray arm is mounted for rotation about an axis of rotation, wherein the spray arm bears at a distance from the axis of rotation a nozzle which is adapted to be acted upon with cleaning fluid subject to pressure and to revolve around the axis of rotation together with the spray arm for the purpose of acting on the surface to be cleaned with a stream of fluid, and comprising a protective disk which covers the at least one spray arm towards the open underside of the housing and defines a ring-shaped fluid passage for the stream of fluid to pass through, this fluid passage being penetrated by retaining bars, wherein the at least one spray arm is rotatable relative to the protective disk.
Such a surface cleaning head is known from U.S. Pat. No. 3,832,069. It is suitable, for example, for the cleaning of hard surfaces, for example the surfaces of terraces, garage entrances and also garage doors. The pressure line of a high-pressure cleaning device can be connected to the surface cleaning head for the purpose of cleaning the hard surfaces. Cleaning fluid subject to pressure can then be supplied to the nozzle which is arranged on the at least one spray arm. The cleaning fluid can be applied to the surface to be cleaned with the aid of the nozzle. The nozzle thereby experiences a recoil, under the influence of which the spray arm is caused to rotate about the axis of rotation. This makes it possible to act on a relatively large surface area with cleaning fluid within a short time.
In order to prevent objects arranged on the surface to be cleaned, for example pebbles, reaching the area of the at least one spray arm, a protective disk is arranged beneath the spray arm in the case of the surface cleaning head known from U.S. Pat. No. 3,832,069. This defines a fluid passage so that the stream of fluid proceeding from the nozzle can reach the surface to be cleaned. The fluid passage is penetrated by several retaining bars which extend as far as a side wall of the housing and, as a result, stabilize the protective disk.
The stream of fluid rotating about the axis of rotation impinges at time intervals on a retaining bar which penetrates the fluid passage. As a result, the protective disk is caused to oscillate and this leads to a clearly audible noise.
The object of the present invention is to develop a surface cleaning head of the generic type further in such a manner that it generates less noise.